Gross Anatomy II - Week 1 Notes PDF

Gross Anatomy II Home Upper Extremity Nerve Innervati… Week 14 Lecture N Week 1 Notes : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 1 of 14 Axioappendicular and Scapulohumeral Muscles Objectives 1. Name the anterior and posterior axioappendicular muscles 2. Name th...

Gross Anatomy II Home Upper Extremity Nerve Innervati… Week 14 Lecture N Week 1 Notes : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 1 of 14 Axioappendicular and Scapulohumeral Muscles Objectives 1. Name the anterior and posterior axioappendicular muscles 2. Name the scapulohumeral (intrinsic shoulder) muscles and describe their origin, insertion, action and nerve supply 3. Name the rotator cuff muscles and understand their importance for the stability of the shoulder joint 4. Describe the boundaries and contents of the quadrangular space, triangular space, and triangular interval 5. Describe the origin, course, branches and distribution of the axillary nerve 6. Discuss common disorders affecting the axioappendicular and scapulohumeral muscles and related structures Axioappendicular Muscles (mostly learned about in gross 1 and DAA) muscles connecting axial skeleton to skeleton of upper limb groups: anterior and posterior posterior axioappendicular muscles (superficial muscles of the back): trapezius, latissimus dorsi, levator scapulae (notice that the middle and uppper trap (in green) had to be removed on the left to be able to see the levator scapulae (in pink) , rhomboid minor and rhomboid major (notice that trap has been removed to visualize the rhomboids). : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 2 of 14 anterior axioappendicular muscles: pectoralis major, after pec major is removed, you can now visualize pectoralis minor, subclavius and serratus anterior : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 3 of 14 Scapulohumeral (Intrinsic Shoulder) Muscles muscles that extend from shoulder girdle (clavicle and scapula) to humerus involved in movements of arm at shoulder joint components: deltoid supraspinatus infraspinatus teres minor : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 4 of 14 teres major subscapularis Deltoid Bony Attachments: 1: Lateral clavicle, acromion, spine of scapula. 2: Deltoid tuberosity of the humerus. Innervation: Axillary nerve (C5,6) from the posterior cord of the brachial plexus. Arterial Supply: Posterior circumflex humeral a. Action: Abducts arm; anterior fibers flex & medially rotate the arm; posterior fibers extend & laterally rotate the arm. Supraspinatus - Rotator Cuff Muscle Bony Attachments: 1: Supraspinatous fossa. 2: Upper facet of the Greater tubercle of the humerus. Innervation: Suprascapular nerve (C5,6) from the superior trunk of the brachial plexus. Arterial Supply: Suprascapular a. Action: Abducts the arm (initiates abduction). Infraspinatus - Rotator Cuff Muscle Bony Attachments: : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 5 of 14 Bony Attachments: 1: Infraspinatous fossa 2: Middle Facet of the greater tubercle of the humerus. Innervation: Suprascapular nerve. Arterial Supply: Suprascapular a. Action: Laterally rotates the arm. Teres minor - Rotator Cuff Muscle Bony Attachments: 1: Upper 2/3 of the lateral border of the scapula. 2: Greater tubercle of the humerus. Innervation: Axillary nerve (C5,6) from the posterior cord of brachial plexus. Arterial Supply: Circumflex scapular a. Action: Laterally rotates the arm. Teres major Bony Attachments: 1: Dorsal surface of the inferior angle of the scapula. 2: medial lip of bicipital (intertubercular) groove of humerus (crest of lesser tubercle) Innervation: Lower subscapular nerve (C5,6) from the posterior cord of the brachial plexus. Arterial Supply: Circumflex scapular a. Action: Adducts the arm, medially rotates the arm, assists in arm : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 6 of 14 Action: Adducts the arm, medially rotates the arm, assists in arm extension. Subscapularis - Rotator Cuff Muscle Bony Attachments: 1: Medial two-thirds of the costal surface of the scapula (subscapular fossa). 2: Lesser tubercle of the humerus. Innervation: Upper and lower subscapular nerves (C5,6). Arterial Supply: Subscapular a. Action: Medially rotates the arm; assists extension of the arm. : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 7 of 14 look for the dots below the picture to scroll to see all the photos. : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 8 of 14 Rotator Cuff stability of shoulder joint has been sacrificed in order to allow a wide range of motion. It is the most commonly dislocated large joint its strength almost entirely depends on tone of short muscles connecting scapula to upper end of humerus and rotator cuff muscles: supraspinatus (superiorly) infraspinatus (posteriorly) teres minor (posteriorly) subscapularis (anteriorly) Stop and think: Which part of the joint is the least supported? hint... look at where all the muscles are. What looks the least supported? Quadrangular Space space that communicates axilla with posterior aspect of shoulder region boundaries (posterior view): superiorly: teres minor inferiorly: teres major medially: long head of triceps brachii laterally: humerus (surgical neck) transmits axillary nerve and posterior circumflex humeral vessels : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 9 of 14 Quadrangular space represented in a drawing : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 10 of 14 Triangular (Upper Triangular) Space smaller space located medial to quadrangular space boundaries (posterior view): superiorly: teres minor inferiorly: teres major laterally: long head of triceps brachii contains circumflex scapular vessels : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 11 of 14 Triangular Space represented in a drawing. : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 12 of 14 Triangular Interval (Lower Triangular Space) boundaries (posterior view): superiorly: teres major medially: long head of triceps brachii laterally: shaft of humerus radial nerve and profunda brachii vessels pass through this interval to reach posterior compartment of arm : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 13 of 14 Axillary Nerve originates from posterior cord of brachial plexus in axilla (terminal branch) contains fibers from ventral rami of C5 and C6 passes posteriorly, through quadrangular space, inferior to shoulder joint (vulnerable to damage during shoulder dislocations) STOP AND THINK: why is this nerve vulnerable during shoulder locations? branches: muscular branches to deltoid and teres minor articular branch to shoulder joint upper lateral cutaneous nerve of arm (superior lateral brachial cutaneous nerve) à supplies skin over superior part of lateral aspect of arm (over lower part of deltoid) : https://sites.google.com/view/grossanatomyii/week-1-notes 5/8/24, 2 17 PM Page 14 of 14